1. Field of the Invention
The invention relates in general to an electrostatic discharge protection device, and more particularly to an electrostatic discharge protection device for eliminating the electrostatic discharge in an optical disc drive to protect the delicate electronic components within the optical disc drive.
2. Description of the Related Art
In the procedure of operating an optical disc drive, a user could hardly avoid touching the optical disc drive. Consequently, electrostatic discharge carried on the user's body is easily transferred to the optical disc drive. Since an optical disc drives is usually equipped with very delicate electronic components, electrostatic discharge has great opportunity causing irreversibly damage to the electronic components as long as electrostatic discharge is transferred to the delicate electronic components.
FIG. 1 is a diagram showing the inside of a conventional optical disc drive. The metallic casing 101 of the optical disc drive 100 has an empty area. Plastic rails 102 are fixed on two sides of the casing 101. Each of the plastic rails 102 has a metallic guide bar 103 to slide upon. The metallic guide bars 103 each have one end blocked by a stopper 104 on the casing 101. The other ends of the metallic guide bars 103 support a tray 105 on its two sides, enabling the tray 105 to move out of the casing 101 completely. Delicate electronic components such as a spindle motor 106 for rotating a disc and an optical pick-up unit 107 on the tray 105 are exposed along with the tray 105. A metallic protection bottom plate (not shown) is disposed beneath the tray 105 for protection. The front end of the tray 105 adjoins a panel 108. An ejection key 109 is disposed on the panel 108 for control. A flexible circuit board 110 is partially attached to the underside of the casing 101. Besides, the flexible circuit board 110 has one end connected to a main board 111 at the rear end of the casing 101, and the main board 111 is fastened to the casing 101 by a screw 112 to achieve the ground effect. The other end of the flexible circuit board 110 is connected to the rear end of the tray 105 and is electrically connected to the protection bottom plate.
When a user presses the ejection key 109 to unload a disc, the electrostatic discharge on the user's body is transferred to the protection bottom plate through the chink between the panel 108 and the ejection key 109. The flexible circuit board 110 then transfers the electrostatic discharge to the casing 101 to dissipate the electrostatic discharge. However, the circuit of the flexible circuit board 110 is small and capable of fast removing small but not massive amount of electrostatic discharge. The piling up of electrostatic discharge may cause damage to the delicate electronic components. Furthermore, as a massive amount of electrostatic discharge is transferred in the flexible circuit board 110 mainly used for transmitting signal of data, it easily interferes with the transmitted signal of data, affecting the reliability of the optical disc drive.
The metallic guide bars 103 on the two sides of the tray 105 for supporting the tray 105 are more likely to be touched by the user when replacing a disc. In addition, the guide bars 103 are isolated from the path of dissipating electrostatic discharge to ground by the plastic rails 102 and tray 105. The guide bars 103 are prone to accumulate electrostatic discharge unfavorable to the delicate electronic components within the optical disc drive. Therefore, a reliable electrostatic discharge protection device should be installed in an optical disc drive to solve the problem caused by electrostatic discharge.